Thursday, March 24, 2011

In early June 2009 I made a sound recording of a Whinchat (Saxicola rubetra) in Glen Brerachan in Perthshire, Scotland. It was early morning (0540h), misty and a light drizzle was threatening to become heavier. Within a ten minute period this male surprised me with its vocal mimicry as it sang from a silver birch slope overlooking a juncus rush marsh. I recognised at least 15 avian species plus the sound of a distant lamb (of which there were several grazing nearby) and quite probably a frog (also abundant in the area). Several other phrases may have been from unknown species picked up in the wintering quarters in Africa. The Corn Bunting/Corncrake combination suggests that this bird may have been reared, or spent a previous breeding season, in either the Inner Hebrides or even Eastern Europe (if Thrush Nightingale is indeed what is replicated below). However, Scottish-ringed birds have been recovered on migration in Morocco, Iberia and France (BTO/The Birds of Scotland, 2007) and first-year birds may learn from other species in these areas. The rain put paid to further recording and I did not manage to find time to revisit the area later in the week. I tried to locate this bird again in 2010 but did not find it.

The following sonograms are from a single male Whinchat mimicking at least 15 avian species (plus lamb & frog!) in a 10 minute period.

Wednesday, March 16, 2011

A few weeks ago when I passed through Madrid I observed White Storks nesting colonially in Casa de Campo. Pairs were displaying on the nest and in fact both sexes appeared to perform the same display. This involves some very strange looking postures in which the bird begins to squat and rapidly (though fairly gracefully) throw its head backwards with the neck bending right back until the head is resting on the back. Then, more slowly, the head is brought back forward, continuing until the whole bird was leaning forward, tailed raised, wings half-open, until the bill touches the nest. Some single birds appeared more aggressive in their display, particularly as other storks flew in and landed on neighbouring trees and it probably performs different functions in different situations. The display is often accompanied by loud bill clattering which was difficult to hear as some nearby construction involving pneumatic drills made this a little difficult.

Monday, March 14, 2011

The course of an old railway line between Knockentiber and Springside in Ayrshire provides some good scrubby habitat for Yellowhammers (Emberiza citrinella). While surveying the territorial males there last May, I heard one bird that was singing two song types which were alternated almost one after the other. Most of the birds in this area sing about eight strophes (or deliveries) per minute and stick to one song type for quite long periods, though occasionally dropping the final ‘cheese’ phrase. Listen to this excerpt of a recording below of this bird and you’ll see what I mean. The first strophe I’ve termed the ‘Fast High’ song type/strophe and the second, the ‘Slow Low’ song type/strophe.

The ‘Fast High’ strophe is around 1.84 seconds with the first phrase comprised of a rattle of 10-11 syllables spanning 4.22-6.76 kHz and lasting 1.07 secs. The second phrase – just a single element, and the familiar ‘cheese’ of the popular British mnemonic for this species – is around 4.85 kHz and lasting 0.68 secs.

The ‘Slow Low’ strophe is longer at around 2.11 seconds with usually 12 lower-pitched rattles spanning 3.07-5.04 kHz and lasting 1.37 secs. The 'cheese' phrase is also lower pitched at 4.4 kHz, lasting 0.55 sec.

Another element in the song that is quite difficult to detect in the field with the human ear (and while listening to playback of recordings) is the very short (0.04 secs) and high pitched (up to 8 kHz) element that immediately proceeds the rattle. It is visible on the sonogram but see if you can pick it out in the recording.